The invention relates to a closing device for a filling tube of a fuel tank in an automobile according to claim 1.
It is known to sealingly join the filling tube of a fuel tank in an automobile to a socket of a trough in the body which, in turn is outwardly opened and can be closed, for example, by a flap or threaded plug. It is further known to form this trough as a separate plastic component which can be snappingly inserted into the body opening. There are increasing demands that such devices should be formed so as to allow for automatic fuelling. There is a further demand that no fuel should leak out in a normal operation. In addition, impurities are to be prevented from getting into the tank from outside. Finally, arrangements are to be made for fuel residues left from fuelling, which collect in the lower area of the trough, to be discharged downwards.
From FR 27 61 934, it has become known to provide a closing flap at the end of a filling tube for a fuel tank in an automobile. The flap opens inwardly and is provided with a sealing which interacts with a sealing edge in the interior of the socket. During fuelling, the flap is pivoted open by means of the fuel nozzle against the force of a spring. Achieving sufficient sealing requires that the closing force of the spring be of a certain magnitude. However, its disadvantage is that the fuel nozzle needs to be pushed in at a considerable force to open the closing flap. Pulling the fuel nozzle out also involves problems because the spring-loaded closing flap counteracts it by a resistance. A further disadvantage is that the constructional expenditure is rather large for a flap and a spring.